Machine for bending sheet metal



July 21, 1931. M. I HNRICH MACHIHNEIEFOR BENDING SHEET METAL Filed March17, 1950 2 Sheets-Sheet 1 ATTORNEYS Patented July 21, 1931 I 1 UNITEDSTATES PATENT OFFICE;

ROBERT M. HINRICH, or DETROIT, MICHIGAN, ssrenon To DRAKE-AVERY COMPANY,

013 DETROIT, MICHIGAN, A CORPORATION or: MICHIGAN MACHINE FOR BENDISHEET TAL,

The invention relates to machines for bending sheet metal of the generaltype known as brakes. It is the object of the invention to obtain aconstruction which is particularly designed for the forming of a type ofoint or seam extensively used in sheet metal construction and toaccomplish this with the elimination of a number of operations necessarywith brakes of ordinary construction. To this end the invention consistsin the novel construction as hereinafter set forth.

In the drawings:

Figure l is an end elevation of a brake to which my improvement isapplied;

Figure 2 is a front elevation of a portion of Figure 1;

Figure 3 is a cross section;

Figure 4 is a similar View showing the parts in different positions;

Figures 5 and 5a are cross sections showing the successive operationswith my improved machine;

Figures 6, 6a, 6b, 60, 6d and 6e are cross sections showing thesuccessive operations usually performed for forming the same joint by anordinary construction of brake, and

Figure 7 is a section similar to Figure 3 showing a modifiedconstruction.

The general construction of my improved brake may be of any suitabledesign as hereinafter set forth. It comprises essentially a bed or tableA having a depending front flange B and a movable jaw or clamp O whichis raised or lowered by any suitable means such as the lever D andeccentrics E. F is a bending leaf which normally lies parallel to theflange B and which is pivoted at G in alignment with the corner at theintersection of the table A and flange B.

The parts thus far described are common to other constructions of brakesand may be used for forming various constructions of joints by a seriesof distinct bending operations. Thus Figures 6 to 6d inclusive show thesuccessive operations for forming one type of joint as follows: InFigure 6 the sheet metal blank 1 clamped by the member C has a flange 2bent at right angles through the raising of the leaf F. By a distinctoperation shown in Figure 6a a portion 3 of the flange 2 is bent atright angles to form a Z-shaped construction. By a third operation shownin Figure 6b the portion 2 is bent at an acute angle to the portion 1and by a succeeding operation Figure the portion 3 is bent at an acuteangle to the portion 2. By

a fifth operation, Figure 6d, the structure is flattened down to formreturn bends 4f and 5 and by a sixth operation Figure 6c the por-. tion1 is pressed up into the plane of the portion 3. p

To avoid the necessity of performing all of these successive operations,I have designed a construction in which with only two. operations the:joint is completely formed. This asshown' in Figure 3 comprises a memberH which may be laid upon the bed A to raise the level thereof butterminating short of the front flange B to form by the bed a lower stepI, The leaf F has attached to its front face an upwardly projectingflange J and'the clampingmember C has attached to its outer face a stepK with a downwardly projecting flange L. The arrangement is such that byfirst placing the sheet metal blankupon the bed and clamping the same bythe member Cwith aportion projecting outwardly, the wing F may then beswung upward. into the position shown in Figure 4. This bends the metalinto av Z-shaped form with two acute angle bends, one formed aroundtheedge of'the clamping member 6' and the otherby the co-operation of. theprojecting flanges J andL together with the step K. At-the completionof. this operation the clamp is released, the leaf-F lowered and theblank with the z-shaped bend therein ismoved inward so as to bebeneaththe raised clamp C; This clamp is then lowered into theposition shown inFigure 3 where the Z- shaped bend is flattened. down into the re-. cessformed by the step I, forming the structure as shown inFigure 5a. Thuscompleted structure includesthe two portions M andM which are arrangedin the same plane and the reverse return bent portions M and M thelatter being off-set as shown.

In the modified construction shownin Figure 7', the onlydifl'erence, isthe placing of a proj eating-portion N. ontheclamping member C whichregisters with the recess formed by the step I. With this structure whenthe sheet metal blank is first clamped by the depression of the member 0it will simultaneously form an off-set portion between the projection Nand the step I. The leaf F is then swung upward to bend this offsetportion into the Z form, after which the clamp is released, the Z-shapedportion is moved inward beneath the portion I and the clamp is againdepressed to flatten down the bend. In other words, in the constructionshown in Figures 3 and 4 the off-set is formed in the final operationwhereas with the construction shown in Figure 7 the off-set is formed inthe initial operation but the final structure is the same in eachinstance.

My improved machine will greatly expedite the forming of the seam andthus will considerably reduce the cost of the labor.

IVhat I claim as my invention is:

1. A sheet metal brake comprising a bed, a clamping head above said bedhaving an acute angular edge portion, a swinging leaf for bending aprojecting portion of a blank clamped by said head and bed over saidacute angular edge, co-operating means on said swinging leaf and saidhead for forming a reverse acute angular bend in said blank and a raisedportion on said bed for supporting the blank removed from the edge toform a recess into which said reverse acute angular bends may becollapsed by the clamping pressure of said head to form in said blank anoffset double return bend.

2. A sheet metal brake comprising a bed, a clamping head having an acuteangular edge portion, a swinging leaf pivoted on an axis adjacent tosaid acute angular edge, an acute angular bent edge carried by said leaffor engaging a projecting portion of a sheet metal blank clamped by thesaid head and bed to bend the same over said first mentioned angularbending edge, and a member on said clamp co-operating with the acuteangular bending edge on said leaf for forming a reverse acute angularbend in said blank and a raised portion on said bed for supporting theblank removed from the edge to form a recess into which the reverseacute angular bends in said blank may be collapsed to form in said blanka laterally off-set double return bend.

3. A sheet metal brake comprising astepped bed, a clamping headextending over the step in said bed and provided with an acute angularedge portion, a swinging leaf pivoted upon an axis adjacent to saidacute angular edge, an acute angular edge portion carried by said leafand adapted to bend a projecting portion of a sheet metal blank clampedby the said head and bed about acute annular edge on said head, a memberprojecting from said head,fco-operating with the acute angular edgeportion on said leaf for forming in saidblanka reverse acute angularbend

